Effect of the high pressure on the structure and intercalation properties of lithium-nickel-manganese oxides

Journal Article · Fri Jun 15 00:00:00 EDT 2007 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2007.03.025· OSTI ID:21015842

Yoncheva, M ^[1]; Stoyanova, R ^[1]; Alcantara, R ^[2]; Ortiz, G ^[2]; Tirado, J L ^[2]

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1. Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria)
2. Laboratorio de Quimica Inorganica, Facultad de Ciencias, Universidad de Cordoba, 14071 Cordoba (Spain)

Lithium-nickel-manganese oxides (Li{sub 1+} {sub x} (Ni{sub 1/2}Mn{sub 1/2}){sub 1-} {sub x} O{sub 2}, x=0 and 0.2), having different cationic distributions and an oxidation state of Ni varying from 2+ to 3+, were formed under a high-pressure (3 GPa). The structure and cationic distribution in these oxides were examined by powder X-ray diffraction, infrared (IR) and electron paramagnetic resonance (EPR) in X-band (9.23 GHz) and at higher frequencies (95 and 285 GHz). Under a high pressure, a solid-state reaction between NiMnO{sub 3} and Li{sub 2}O yields LiNi{sub 0.5}Mn{sub 0.5}O{sub 2} with a disordered rock-salt type structure. The paramagnetic ions stabilized in this oxide are mainly Ni{sup 2+} and Mn{sup 4+} together with Mn{sup 3+} (about 10%). The replacement of Li{sub 2}O by Li{sub 2}O{sub 2} permits increasing the oxidation state of Ni ions in lithium-nickel-manganese oxides. The higher oxidation state of Ni ions favours the stabilization of the layered modification, where the Ni-to-Mn ratio is preserved: Li(Li{sub 0.2}Ni{sub 0.4}Mn{sub 0.4})O{sub 2}. The paramagnetic ions stabilized in the layered oxide are mainly Ni{sup 3+} and Mn{sup 4+} ions. The disordered and ordered phases display different intercalation properties in respect of lithium. The changes in local Ni,Mn-environment during the electrochemical reaction are discussed on the basis of EPR and IR spectroscopy. - Graphical abstract: Lithium-nickel-manganese oxides (Li{sub 1+} {sub x} (Ni{sub 1/2}Mn{sub 1/2}){sub 1-} {sub x} O{sub 2}, x=0 and 0.2), having different cationic distributions and an oxidation states of Ni varying from 2+ to 3+, were formed under a high-pressure (3 GPa)

• OSTI ID: 21015842
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 6 Vol. 180; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
CLATHRATES
ELECTRIC BATTERIES
ELECTROCHEMISTRY
ELECTRON SPIN RESONANCE
GHZ RANGE 01-100
INFRARED SPECTRA
LITHIUM IONS
LITHIUM OXIDES
MANGANESE IONS
MANGANESE OXIDES
NICKEL IONS
NICKEL OXIDES
PARAMAGNETISM
PRESSURE RANGE GIGA PA
SYNTHESIS
X-RAY DIFFRACTION